Adjustable head wrenches are well known in the art and typically have one adjustable jaw and one stationary jaw for engaging objects of different dimensions within the adjustment range of the wrench. In many wrenches having an adjustable head, a worm gear member is fixed to the body of the wrench and is geared to corresponding teeth in the jaw to be moved. In many instances, the worm gear is rotated with the user's thumb. As the worm gear is rotated, the movable jaw's teeth are engaged by the gear and carry the movable jaw over the worm gear to adjust the distance between the stationary jaw and the movable jaw.
When in use, a user must manipulate the worm gear each time the user wishes to engage a different sized object, such as a nut or bolt, to adjust the size of the wrench head accordingly. When sequentially engaging nuts or bolts of varying dimensions, it may be commonly required for a user to adjust the wrench head size for each individual nut or bolt. Having to repeatedly adjust the distance between the two jaws of the wrench can be inconvenient to a user, especially when the user is working with multiple nut and bolt sizes. Additionally, when using an adjustable head wrench, a user is often required to remove the wrench head from the nut or bolt, reposition the wrench head, and reengage the wrench head with the nut or bolt when making a series of partial turns to tighten or loosen the same. Repeatedly having to engage is such steps can be inconvenient to a user.
Pliers-type wrenches are also well known in the art and typically include two handles attached to a set of jaws, wherein each handle is coupled to a separate jaw, and a pivot point in proximity with the jaws. Typically, the leverage provided by the handles of such wrenches increases as the proximity of the pivot point to the jaws increases, and as such, so does the mechanical advantage that is provided to a user. However, because the handles and jaws act as levers, the ends of the handles are generally spread apart farther than the opening between the jaws. For example, if the handles are four times longer than the jaws (generally a mechanical advantage of four), then the handles will need to be spread apart four times farther than the desired opening between the jaws. Because the space in which a user may operate pliers-type wrenches is often limited due to spatial constraints such as hand size or available work space, traditional pliers-type wrenches may only be able to provide a user with a very limited amount of leverage in such instances.
Accordingly, it can be seen that needs exists in the art for an automatic adjustable head wrench that permits a user to forego repeatedly adjusting the wrench head size and does not require a user to reposition the wrench head on a nut or bolt when making consecutive turns to tighten or loosen the same. Additionally, needs exist for an adjustable head wrench that foregoes the leverage problems associated with pliers-type wrenches. Therefore, it is to the provision of these needs and others that the present invention is primarily directed.